David Cameron has led efforts to reassure the public that UK intelligence services operate within the law as the Government faced questions over eavesdropping agency GCHQ's reported links to a US internet monitoring programme.

The Prime Minister declared that he was personally satisfied "that they operate in a way that is proper and that is fitting".

Documents leaked by former CIA worker Edward Snowden suggest GCHQ have had access to a US spy programme since at least June 2010.

Prism is said to give the National Security Agency and FBI easy access to the systems of nine of the world's top internet companies, including Google, Facebook, Microsoft, Apple, Yahoo and Skype.

Foreign Secretary William Hague declined to confirm or deny the claimed UK links when he appeared before MPs to be grilled on the issue, insisting he would say "nothing that gives any clue or comfort to terrorists, criminals or foreign intelligence services".

He said Britain deplored the leak by Mr Snowden - who has sought refuge In Hong Kong - but said Britain's systems of checks and balances on its intelligence services "could be the strongest in the world".

And he insisted intelligence sharing with the US was more important than ever in the face of mounting terror and other threats - pointing to a big spike in activity ahead of the Olympic Games in London last year.

Initial information has been handed over to the Intelligence and Security Committee (ISC) - which carries out parliamentary scrutiny of covert operations - and it is due to receive a full report from GCHQ on Tuesday, he told the Commons.

In the year to May 2012, it is reported to have generated 197 intelligence reports via Prism. But Mr Hague told MPs that any suggestion it was part of an effort to circumvent the law to obtain information was "baseless".

"It has been suggested that GCHQ uses our partnership with the United States to get around UK law, obtaining information that they cannot legally obtain in the United Kingdom," he said in statement. "I wish to be absolutely clear that this accusation is baseless."